This invention relates to apparatus for treating webs of material in general and more particularly to apparatus for treating webs of material with at least one rotatable cylinder which engages the web of material, is freely movable in the vertical direction, but guided in the horizontal plane, the cylinder being in a trough which extends over the length of the cylinder and contains liquid, at least the lower portion of the cylinder immersed in the liquid.
An apparatus of this general nature is described in DE-AS No. 10 87 443. In the known design, the cylinder is sealed all around with respect to the upper edge of the trough and the liquid in the trough is maintained under pressure so that the cylinder is pushed upwards out of the trough while it rests against a counter cylinder arranged on top thereof and, together with the latter, forms a roll gap, in which a web of material which is not sensitive to the moisture on the cylinder, i.e., consists preferably of textiles, can be squeezed out under considerable pressure. The pressure is exerted very uniformly over the width of the web because it is brought about by the uniform pressure of the liquid in the trough. The idea, on which the known design is based, comprises integrating the increase of the pressure in the liquid in order to obtain a correspondingly intensive squeezing-out effect. Due to the long seals, tightness problems arise. A considerable part of the drive power is lost in overcoming the friction at the seals. The operating velocity of the design is limited. The device for generating the pressure represents additional costs.
Apparatus, in which a hollow cylinder floating in a liquid rests from below against two mutually parallel cylinders which are arranged at approximately the same height with lateral spacing and forms roll gaps therewith, is known per se from French Pat. No. 1,123,519.
It is an object of the present invention to simplify apparatus of the type described in DE-AS No. 10 87 443 and to make it also suitable for higher velocities.